A sense of depression pervades Westminster. It isn't just MPs: anyone who believes in the power of politics for good is weighed down by this misery.

But what infuriates me is that this huge festering corrosive mess is of our own making.

Every time I hear an MP found out for "flipping", tax avoidance or profiteering argue they were just following the rules and that the rules now need to change I find myself yelling at the television: "Where were you when we had a chance to change the rules last summer? You were voting in the other lobby!"

The rules were (and still are) so vague that all manner of personal wealth creation on the public purse was perfectly possible. Believe it or not, even in my constituency, just half an hour from Westminster, I am eligible to claim £24k for a second home and all the trappings. I have never claimed as it would be utterly outrageous to do so, but plenty of London MPs have with wild abandon.

What I can't understand is how some MPs thought this or other practices gracing the papers this week were ever a good idea. How did they not realise that sooner or later people would find out they had a second home 40 minutes from their first one, both in easy commuting distance of parliament? Or that they'd renovated the bathroom in several properties at our expense by flipping? Or that they'd used taxpayers' money to clean a swimming pool? What planet were they living on when they thought the British public would wear this?

It is as if MPs have been blissfully marooned in a separate annex sound-proofed from the screaming howls of the public outside, who look on in disbelief at our largesse.

Yes, it is inevitable with so much mud that relative bystanders at the trough will find unfair allegations flung their way. But that is a consequence of our failure to tackle the issue. We have had so many opportunities to prevent this week's horror. And at every stage MPs have bottled it.

Parliament should have submitted itself to freedom of information legislation years ago, instead of fighting it at every turn. It should never have required a criminal act of theft to shine daylight on these claims.

And we should have changed the rules last summer to stop MPs from profiting from the second home allowance. Instead of which MPs trooped through the lobbies to vote down moderate proposals to abolish the John Lewis list and cut the overall allowance.

For months after last year's failed vote, Nick Clegg pressed Gordon Brown to sit down with opposition parties and fix the system urgently, but his pleas were ignored. Then with weeks to go before publication of receipts, Brown rushed to scrap the second home allowance and replace it with one allowing MPs to go on claiming money but with less scrutiny. The only feeble positive reform voted through a fortnight ago was to abolish second home allowances for London MPs from 2010.

The impact of this coverage has been so disastrous for faith in politics, I actually think it is now too late just to propose a new set of reforms and hope it will go away. The only way any of us are going to have the authority to do our job again is to vote through drastic new reforms abolishing capital gain, personal profit and private furnishings and then dissolve parliament to let the public have their say. Until then, the acid of public scorn will go on dissolving the fabric of democracy, undermining our capacity to campaign for change on anything in any area of public policy.

But it won't happen. We'll all just carry on as before, in our own little world, deaf to reality. And we will blame everyone but ourselves for parliament's misfortune. What a sorry mess.